Sympathectomy refers to the destruction of tissue anywhere in either of the two sympathetic trunks, long chains of nerve ganglia lying along either side of the spine. Each trunk is broadly divided into three regions: cervical (up by the neck), thoracic (in the chest) and lumbar (in the lower back). The most common area targeted in sympathectomy is the upper thoracic region, that part of the sympathetic chain lying between the first and fifth thoracic vertebrae.

Scientists became fascinated with the idea of sympathectomy in the mid-19th century when it was learned that the autonomic nervous system runs to almost every organ, gland and muscle system in the body, and it was surmised that somehow these nerves must play a role in how the body is able to automatically adjust levels on many different body functions in response to changes in the environment, exercise and emotion. They wondered how exactly it was that the autonomic nervous system was able to do all that, and they wondered what might change if various parts of it were removed.

A lumbar sympathectomy was also developed and used to treat excessive sweating of the feet and other ailments, and typically resulted in impotence in men.

Sympathectomy itself is relatively easy to perform; however, accessing the nerve tissue in the chest cavity by conventional surgical methods was difficult, painful, and spawned several different approaches. The posterior approach was developed by Dr. A.W. Adson in 1908, and required resection (sawing off) of ribs. Dr. E.D. Telford came up with a supraclavical (above the collar-bone) approach in 1935, which was less painful than the posterior, but was more prone to damaging important nerves and blood vessels.

Because of these difficulties, and because of disabling sequelae associated with sympathetic denervation, conventional or "open" sympathectomy was never a very popular procedure, although it continued to be practiced for hyperhidrosis, Raynaud's disease, and various psychiatric disorders. With the popularization of lobotomy in the 1940s, sympathectomy fell out of favor when utilised as psychosurgery.

The endoscopic version of thoracic sympathectomy was pioneered by Drs. Goren Claes and Christer Drott at the Borås hospital in Sweden in the late 1980s. The development of endoscopic "minimally invasive" surgical techniques have made possible the mass-marketing of sympathectomy, and today endoscopic thoracic sympathectomy (ETS) surgery is practiced in many countries throughout the industrial world. The total number of ETS surgeries performed worldwide to date numbers well over 100,000.

In addition to hyperhidrosis and Raynaud's, the indications for ETS have expanded to include facial blushing, and, once again, psychiatric disorders such as social phobia and agoraphobia. There are reports of ETS being used to treat headaches and hyperactive bronchial tubes.

In the mid 1990s a group of Swedish ETS patients complaining of disabling side effects formed the organization FFSO (people disabled by sympathectomy). The group grew to over 300 members (about 0.3% of estimated world-wide number of patients).